C/C++ abs(), labs(), llabs()用法及代碼示例

在cstdlib頭文件中定義了abs()，labs()，llabs()函數。這些函數返回作為其參數輸入到它們的整數的絕對值。

1. abs()函數：此函數的輸入是C中int類型的值和C++中int類型，long int或long long int的值。在C中，輸出是int類型，在C++中，輸出具有與輸入相同的數據類型。下麵是示例C++程序，以顯示abs()函數的工作。

   // CPP program to illustrate 
   // abs() function 
   #include <cstdlib> 
   #include <iostream> 
     
   using namespace std; 
     
   int main() 
   { 
       int val1, val2; 
     
       /// finding absolute value using 
       /// abs() function. 
       val1 = abs(22); 
       val2 = abs(-43); 
     
       cout << "abs(22) = " << val1 << "\n"; 
       cout << "abs(-43) = " << val2 << "\n"; 
       return 0; 
   }

   Output:
   abs(22) = 22
   abs(-43) = 43
   

2. labs()函數：這是abs()函數的long int版本。輸入和輸出均為long int類型。下麵是示例C++程序，以顯示labs()函數的工作。 post_top_responsive

   // CPP program to illustrate 
   // labs() function 
   #include <cstdlib> 
   #include <iostream> 
     
   using namespace std; 
     
   int main() 
   { 
       int val1, val2; 
     
       /// finding absolute value using 
       /// labs() function. 
       val1 = labs(1234355L); 
       val2 = labs(-4325600L); 
     
       cout << "labs(1234355L) = " << val1 << "\n"; 
       cout << "labs(-4325600L) = " << val2 << "\n"; 
       return 0; 
   }

   Output:
   labs(1234355L) = 1234355
   labs(-4325600L) = 4325600
   

3. llabs()函數：這是abs()函數的long long int版本。輸入和輸出均為long long int類型。下麵是示例C++程序，以顯示llabs()函數的工作。

   // CPP program to illustrate 
   // llabs() function 
   #include <cstdlib> 
   #include <iostream> 
     
   using namespace std; 
     
   int main() 
   { 
       int val1, val2; 
     
       /// finding absolute value using 
       /// labs() function. 
       val1 = llabs(1234863551LL); 
       val2 = llabs(-432592160LL); 
     
       cout << "llabs(1234863551LL) = " << val1 << "\n"; 
       cout << "llabs(-432592160LL) = " << val2 << "\n"; 
       return 0; 
   }

   Output:
   llabs(1234863551LL) = 1234863551
   llabs(-432592160LL) = 432592160